Supplementary Material: High vapor pressure deficit drives salt-stress induced rice yield
losses
This document contains supplementary material for the article titled “High vapor pressure deficit
drives salt stress induced rice yield losses in India.” All information contained in this document
is referenced in the text of the main article. Tables and figures are referenced with a leading “S”.
Supplementary Table S1
Supplementary Figures S1-S18
Supplementary Tables:
Table S1. Marginal effects of weather variables expressed per standard deviation (SD)
Day Hours above 33°C
Growth Phase
Pre-Flowering
SD based on
residual variation
80.9 (hours)
Marginal effect
(% change per SD)
9.27
Night Hours above 22°C
Pre-Flowering
84.7 (hours)
-9.02
Vapor Pressure Deficit
Pre-Flowering
0.22 (kPa)
-11.8
Variable
Post-Flowering
0.37 (kPa)
5.57
Marginal effects are shown only for weather variables whose estimated regression parameters were significant at
P<0.1 (see Model 4 in Table 3) and were calculated by multiplying regression parameters by the SDs of the
corresponding weather variables. SDs refer to residual variation after removing variation explained by fixed effects
for location, cultivar, and soil type.
Supplementary Figures:
Rice Yields
15,000
Electrical Conductivity
14
13
12
10,000
5,000
Deci-siemens per meter
11
10
9
8
7
6
5
4
3
2
1
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
0
Fig. S1. Annual box-plots for rice yields and electrical conductivity. Each box is defined by the
upper and lower quartile, with the median depicted as a horizontal line within the box. The
endpoints for the whiskers are the upper and lower adjacent values, which are defined as the
relevant quartile +/- three-halves of the interquartile range, and circles represent data points
outside of the adjacent values.
Vapor Pressure Deficit, Pre-flower
3
Vapor Pressure Deficit, Post-flower
4
2.5
Kilopascals
2
1.5
2
1
1
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
0
1998
.5
1997
Kilopascals
3
Fig. S2. Annual box-plots for vapor pressure deficit. Each box is defined by the upper and lower
quartile, with the median depicted as a horizontal line within the box. The endpoints for the
whiskers are the upper and lower adjacent values, which are defined as the relevant quartile +/three-halves of the interquartile range, and circles represent data points outside of the adjacent
values.
Day Hours above 33°C, Post-flower
200
600
150
2008
2007
2006
2005
2004
2003
2002
2001
2000
2008
2007
2006
2005
2004
2003
2002
2001
0
2000
0
1999
50
1998
200
1999
100
1998
400
1997
Hours
800
1997
Hours
Day Hours above 33°C, Pre-flower
Fig. S3. Annual box-plots for cumulative daytime exposure above 33oC. Each box is defined by
the upper and lower quartile, with the median depicted as a horizontal line within the box. The
endpoints for the whiskers are the upper and lower adjacent values, which are defined as the
relevant quartile +/- three-halves of the interquartile range, and circles represent data points
outside of the adjacent values.
Night Hours above 22°C, Pre-flower
Night Hours above 22°C, Post-flower
300
1,200
200
Hours
Hours
1,000
800
100
600
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
2007
2008
2006
2002
2003
2004
2005
2000
2001
1998
1999
0
1997
400
Fig. S4. Annual box-plots for cumulative nighttime exposure above 22oC. Each box is defined
by the upper and lower quartile, with the median depicted as a horizontal line within the box.
The endpoints for the whiskers are the upper and lower adjacent values, which are defined as the
relevant quartile +/- three-halves of the interquartile range, and circles represent data points
outside of the adjacent values.
Cumulative Precip, Pre-flower
Cumulative Precip, Post-flower
1,000
400
2008
2006
2007
2005
2004
2003
2002
0
2000
2001
0
1998
1999
200
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
500
1997
Millimeters
600
Millimeters
1,500
Fig. S5. Annual box-plots for cumulative precipitation. Each box is defined by the upper and
lower quartile, with the median depicted as a horizontal line within the box. The endpoints for
the whiskers are the upper and lower adjacent values, which are defined as the relevant quartile
+/- three-halves of the interquartile range, and circles represent data points outside of the
adjacent values.
1.02
Third Order
Fourth Order
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Electrical Conductivity
.99
1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Electrical Conductivity
1
LB Ratio, Robust over Clustered
8
7.5
7
6.5
6
95% CI, Clustered
.98
Log Yield (kg/ha)
Second Order
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Electrical Conductivity
Fig. S6. Clustering standard errors does not significantly alter the uncertainty around the log
yield predictions in Figure 2. The upper left graph replicates Figure 2 in the text except standard
errors are clustered by the 107 location-year combinations in the data. The upper right graph
reports the ratio of the lower bound for the robust versus clustered confidence interval. The lower
left graph reports the ratio of the upper bound for the robust versus clustered confidence interval.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S7. Replication of Figure 3b for a model that omits the statistically insignificant weather
variables from our preferred specification.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S8. Replication of Figure 3b for a model that extends our preferred specification to include
quadratic precipitation effects.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S9. Replication of Figure 3b for a model that extends our preferred specification to include
an interaction between precipitation and the dummy variable for coastal salinity.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S10. Replication of Figure 3b for a model that extends our preferred specification to include
an interaction between post-flowering vapor pressure deficit and electrical conductivity.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S11. Replication of Figure 3b for a model that extends our preferred specification by
including three growth stages.
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S12. Replication of Figure 3b for a model that extends our preferred specification to include
a linear time trend.
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S13. Replication of Figure 3b for a model that extends our preferred specification to include
a quadratic time trend.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S14. Replication of Figure 3b for a model that extends our preferred specification to include
year fixed effects.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S15. Replication of Figure 3b for a model that extends our preferred specification to include
pH.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S16. Replication of Figure 3b for a model that extends our preferred specification to include
a quadratic function of pH.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S17. Replication of Figure 3b for a model that measures vapor pressure deficit using
average temperature instead of maximum temperature.
5
4
3
Yield (t/ha)
2
1
0
Normal
Inland Saline
0
1
2
3
4
Coastal Saline
Alkaline
5
6
7
8
9 10
Electrical Conductivity
11
12
13
14
15
Fig. S18. Replication of Figure 3b for a model that measures vapor pressure deficit using
minimum temperature instead of maximum temperature.